Conformal Symmetry and Cosmological Entropy Production

• Main Authors: Alexander B. Balakin, Winfried Zimdahl
• Format: Article
• Language: English
• Published: MDPI AG 2002-03-01
• Series: Entropy
• Subjects: general relativity; cosmology; thermohydrodynamics; kinetic theory; inflationary universe
• Online Access: http://www.mdpi.com/1099-4300/4/3/49/

Abstract: Introducing an effective refraction index of an isotropic cosmic medium, we investigate the cosmological fluid dynamics which is consistent with a conformal, timelike symmetry of a corresponding "optical" metric. We demonstrate that this kind of symmetry is compatible with the existence of a negative viscous pressure and, consequently, with cosmological entropy production. We establish an exactly solvable model according to which the viscous pressure is a consequence of a self-interacting one-particle force which is self-consistently exerted on the microscopic particles of a relativistic gas. Furthermore, we show that a suficiently high decay rate of the refraction index of an ultrarelativistic cosmic medium results in an in ationary expansion of the universe.